Field of the Invention
This specification relates to wireless communication and, most particularly, to a method and device for transmitting control information that is used in a terminal (or user equipment) in a wireless communication system.
Related Art
The next generation multimedia wireless communication system, which has recently been very actively and extensively researched and developed, is being request to be evolved as a system that can process and transmit diverse information, such as images, wireless data (or radio data), and so on, excelling the initial voice-based services. For example, hologram and real-time UHD high picture quality services, which can provide higher transmission rates by using a larger amount of frequency resource as compared to the conventional wideband services. Additionally, mission critical services requesting low latency, emergency services or tactical internet service requesting ultimately low latency, and services such as V2X are being requested. Furthermore, massive machine communication, sensor networks, and so on, for supporting a massive number of devices are also be requested.
The purpose of such next generation wireless communication system is to allow reliable communication to be carried out regardless of the position and mobility of multiple users. However, the wireless channel has non-ideal characteristics, such as path loss, noise, fading caused by a multi-path, Inter Symbol Interference (ISI), or a Doppler effect caused by the mobility of the device. A wide range of technology is being researched and developed in order to overcome such non-ideal characteristics of the wireless channel and to enhance reliability in wireless communication.
It is difficult to provide the above-described services by using the Cyclic Prefix-OFDM (CP-OFDM) scheme of the conventional (or legacy) LTE system. Most particularly, by using the conventional LTE system, it is difficult to satisfy the request for low latency communication by using a TTI having the length of 1 ms. Accordingly, new types of waveforms that can satisfy such request are emerging. For example, new waveforms, such as Filter Bank Multi Carrier (FBMC), Generalized Frequency Division Multiplexing (GFDM), Universal Filtered-OFDM (UF-OFMD), FCP-OFDM (Filtered CP-OFDM), and so on, are being discussed as the adequate waveforms for the next generation wireless communication system services. Among such new waveforms, a next generation communication system that demonstrates robustness in asynchronous reception by adaptively adjusting a filter length and a CP duration will hereinafter be described in detail.